Pro-choice counter-demonstraters rally at Powell and Market streets before thousands of anti-abortion protesters parade past in the Walk for Life march from Civic Center Plaza and down Market Street in San Francisco, Calif. on Saturday, Jan. 23, 2016. less

Pro-choice counter-demonstraters rally at Powell and Market streets before thousands of anti-abortion protesters parade past in the Walk for Life march from Civic Center Plaza and down Market Street in San ... more

A line of police officers keep pro-choice demonstrators separated from thousands of anti-abortion protesters participating in the Walk for Life march down Market Street in San Francisco, Calif. on Saturday, Jan. 23, 2016. less

A line of police officers keep pro-choice demonstrators separated from thousands of anti-abortion protesters participating in the Walk for Life march down Market Street in San Francisco, Calif. on Saturday, ... more

Susan Witka, of San Francisco, provides a solitary counter-demonstration as thousands of anti-abortion protesters gather for the Walk for Life rally and march from Civic Center Plaza and down Market Street in San Francisco, Calif. on Saturday, Jan. 23, 2016. less

Susan Witka, of San Francisco, provides a solitary counter-demonstration as thousands of anti-abortion protesters gather for the Walk for Life rally and march from Civic Center Plaza and down Market Street in ... more

Susan Witka, of San Francisco, provides a solitary counter-demonstration as thousands of anti-abortion protesters gather for the Walk for Life rally and march from Civic Center Plaza and down Market Street in San Francisco, Calif. on Saturday, Jan. 23, 2016. less

Susan Witka, of San Francisco, provides a solitary counter-demonstration as thousands of anti-abortion protesters gather for the Walk for Life rally and march from Civic Center Plaza and down Market Street in ... more

An enterprising vendor sells holy action figures where thousands of anti-abortion protesters gather for the Walk for Life rally and march from Civic Center Plaza and down Market Street in San Francisco, Calif. on Saturday, Jan. 23, 2016. less

An enterprising vendor sells holy action figures where thousands of anti-abortion protesters gather for the Walk for Life rally and march from Civic Center Plaza and down Market Street in San Francisco, Calif. ... more

Balloons sway in the wind as thousands of anti-abortion protesters attend the Walk for Life rally and march from Civic Center Plaza and down Market Street in San Francisco, Calif. on Saturday, Jan. 23, 2016.

Balloons sway in the wind as thousands of anti-abortion protesters attend the Walk for Life rally and march from Civic Center Plaza and down Market Street in San Francisco, Calif. on Saturday, Jan. 23, 2016.

Francisco Gonzalez sings for parishoners of St. Charles Church as thousands of anti-abortion protestersgather for the Walk for Life rally and march from Civic Center Plaza and down Market Street in San Francisco, Calif. on Saturday, Jan. 23, 2016. less

Francisco Gonzalez sings for parishoners of St. Charles Church as thousands of anti-abortion protestersgather for the Walk for Life rally and march from Civic Center Plaza and down Market Street in San ... more

Eleven-year-old Mario, from Ceres, Calif., holds on to a makeshift cross as thousands of anti-abortion protesters gather for the Walk for Life rally and march from Civic Center Plaza and down Market Street in San Francisco, Calif. on Saturday, Jan. 23, 2016. less

Eleven-year-old Mario, from Ceres, Calif., holds on to a makeshift cross as thousands of anti-abortion protesters gather for the Walk for Life rally and march from Civic Center Plaza and down Market Street in ... more

Chris and Cristy Enriquez, of American Canyon, can't resist the temptation to have their photo taken with a Super Bowl 50 insignia as thousands of anti-abortion protesters gather for the Walk for Life rally and march from Civic Center Plaza and down Market Street in San Francisco, Calif. on Saturday, Jan. 23, 2016. less

Chris and Cristy Enriquez, of American Canyon, can't resist the temptation to have their photo taken with a Super Bowl 50 insignia as thousands of anti-abortion protesters gather for the Walk for Life rally and ... more

Robert Shauger (center), a deacon from a catholic church in El Dorado Hills, prays with thousands of other anti-abortion protesters during the Walk for Life rally and march from Civic Center Plaza and down Market Street in San Francisco, Calif. on Saturday, Jan. 23, 2016. less

Robert Shauger (center), a deacon from a catholic church in El Dorado Hills, prays with thousands of other anti-abortion protesters during the Walk for Life rally and march from Civic Center Plaza and down ... more

Carlos Negrete and his daughter Maggie, 7, of Sacramento join thousands of other anti-abortion protesters in the Walk for Life rally and march from Civic Center Plaza and down Market Street in San Francisco, Calif. on Saturday, Jan. 23, 2016. less

Carlos Negrete and his daughter Maggie, 7, of Sacramento join thousands of other anti-abortion protesters in the Walk for Life rally and march from Civic Center Plaza and down Market Street in San Francisco, ... more

They came Saturday carrying posters and yellow balloons, stop signs and baby photos. Some drove more than 30 hours from the Midwest, while others walked from their homes around the city.

Together they came — just a day after the 43rd anniversary of the Roe vs. Wade court decision that legalized abortion in the United States — for the San Francisco March for Life. Tens of thousands of antiabortion marchers flooded into the Civic Center Plaza for a rally and then marched along Market Street. “I’ll have nun of it,” read pins attached to the shirts of a youth group. One man carried a wooden cross with a crucified Jesus, and a woman hoisted her infant daughter in the air.

“It’s amazing that all of these people are out here supporting life,” said Cami Mischke, 15, of Tulsa, Okla. “California is one of the top states for abortion. It’s natural that we would want to come here and try and have an impact.”

Cami came to San Francisco in a bus with 105 other parishioners from St. Benedict Church in Broken Arrow, Okla. The group arrived at 4 a.m. Saturday after an almost 30-hour drive. She posed for a photo with a friend in front of City Hall. Both held black signs reading, “I am the pro-life generation.”

“Washington, D.C., is the political side,” she said, referring to the March for Life in the nation’s capital. “But California is the social side. We have already had people come out to oppose us. We love them no matter what they say, and our shouts will be louder.”

Nearby, Nancy Sharpe of Kingsburg (Fresno County) handed out signs to a few friends. Sharpe first attended the rally 12 years ago, and she hasn’t skipped a year since. The marches won’t end until abortion is made illegal, she said.

“People need to understand the sanctity of life, especially young people,” Sharpe said. “Until the genocide of babies ends, until abortion disappears, we will be here marching. It is a tragedy, and it must end.”

The like-mindedness of the protest is what makes it so fun, said Heather Derenzo of Sacramento. It was her eighth year at the event.

“We just want to get the message out that there are better options than abortion,” she said. “It isn’t the right choice in any circumstance. America is still struggling to change the minds of those who think abortion is just a procedure and not the ending of an innocent life.”

But not all agreed. The antiabortion march met a counterprotest at Market and Powell streets. “Abortion is worth fighting for,” the 100 or so protesters shouted. “Women’s dreams are what’s at stake.” Signs reading “When abortion is illegal, women die” and “Fetuses are not babies” were waved in the air.

“Having a choice is important because women have a right to say what happens to their bodies,” said Shira Kindler, 18, of Berkeley. “Having a baby changes your entire life, and not always for the good. There is this misconception that women are having reckless sex and using abortion as the answer. It’s not true — most women get an abortion because they don’t have any other choices.”

Letting women decide

Sam Rodyah, a volunteer from Stop Patriarchy, said the aim of the rally was to make the antiabortion rally uncomfortable and change the terms of the march.

“It is outrageous that this other side represents a vicious attack on women’s rights,” he said. “That shouldn’t be normalized. We want to change the parameters of this fight. It’s about making sure women have a choice over what happens to their bodies.”

As the two groups converged at the same corner, police officers stood at the metal barricades separating the protesters from the marchers. The shouting and sign waving continued as the long line of marchers moved down Market Street.

The march shut down cross traffic across Market Street for hours, snarling downtown traffic for much of the afternoon.

“Traffic was impacted, but there were not problems other than the traffic congestion caused as the march was going down the street,” said Officer Albie Esparza, a San Francisco police spokesman.